671TI Hour meter wire???

[hcalmar]

1979 37C w/ 671TI covingtons. Both hour meters stopped working 6 months apart. Meters and oil pressure switches are fine. If I put a positive charge on the oil pressure switch when the engines are running the meters work. But where does the other wire that is suppose to provide the positive charge come from?????
Thanks
Hal

 

[Fanfare]

You probably have a fuel pressure switch which controls power to the electric hour meters (Hobbs meters) and the battery charger. Follow the fuel line back to the engine block, looking for a bowl shaped device with a few wires coming from terminals at the bottom. That's it. Mine usually fail by leaking fuel. Check your connections with ignition on and off, and with engines running so fuel pressure is present. Some of these switch on with fuel pressure, others switch off. Newer ones do both and have three connections. I was confused by one of these that said "ON" when it was not on. Finally realized I was looking at it upside down, "ON" meant " NO--normally off."

Other boats have hour meters on the tachometer where they are geared to the tach drives. Generally, if the tach works so does the hour meter.

 

[hcalmar]

Thank you. My hour meters are wired to the oil pressure switch tab "B". If I give a positive charge the other tab "A" from an alternate source the meters work when the engines are running. I am trying to find the origional source of the wire that is attached to tab "A". Do you think that is tied into the fuel system?

 

[dsharp]

Is the oil switch running an alarm or just the hour meter. Search "Hobbs" switch and see if you can find a wire diagram. The power usually comes off the ignition switch to the normally "open" oil pressure switch. When the engine starts the switch closes and sends power to the hour meter.